/*
 * Copyright (c) 2009, David A. Freels Sr.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that
 * the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
 *     * Neither the name of the <ORGANIZATION> nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

package net.whippetcode.plugins.intellij.hudson.util;

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathFactory;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathConstants;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ByteArrayInputStream;
import java.net.URL;

/**
 * This class provides utility methods for handling XML.
 * 
 * @author David A. Freels Sr.
 */
public class XMLUtil
{
    private static XPath xpath = XPathFactory.newInstance().newXPath();

    public static byte[] readXML(URL url) throws IOException
    {
        InputStream input = url.openStream();
        int read;
        byte[] buffer = new byte[4096];
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        while ((read = input.read(buffer)) != -1)
        {
            out.write(buffer, 0, read);
        }
        input.close();
        
        return out.toByteArray();
    }

    public static Document createDocument(URL url) throws ParserConfigurationException, IOException, SAXException
    {
        return DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(new ByteArrayInputStream(XMLUtil.readXML(url)));
    }

    public static String getTextElement(String expression, Node node) throws XPathExpressionException
    {
        return xpath.evaluate(expression, node);
    }

    public static NodeList getElements(String expression, Node node) throws XPathExpressionException
    {
        return (NodeList) xpath.evaluate(expression, node, XPathConstants.NODESET);
    }

    public static Node getElement(String expression, Node node) throws XPathExpressionException
    {
        return (Node) xpath.evaluate(expression, node, XPathConstants.NODE);
    }

	public static boolean hasContent(String expression, Node node) throws XPathExpressionException
	{
		String text = getTextElement(expression, node);

		return text != null && text.trim().length() > 0;
	}
}